EX-FLOW instruments are thermal Mass Flow Meters / Controllers of rugged design and suitable for gas flow application in hazardous areas. The intrinsically safe measuring head is tested according to ATEX 95 Directive 94/9/EC and approved under EC-Type Examination Number: KEMA 01ATEX1172, protection II 2 G Ex ib IIC T4 Gb. The housing of the electronics compartment is to IP65 classification. Control valves can either be integrally or separately mounted, to measure and control gas flows (air-equivalent) from:
Gas Flow Control
An EX-FLOW Mass Flow Controller has a control valve with fast and smooth control characteristics. The flow meter and valve should be connected (via separate cables) to a power supply with galvanic isolation / preamplifier / readout system (located in the safe zone) which contains a controller board to complete the control loop. The control valve receives its input from the controller board and immediately responds to any deviation between the output signal from the flow sensor and the setpoint signal.
Bronkhorst High-Tech applies two sorts of coils:
Style “XB” = intrinsic safe coil; needs safety barrier.
protection II 1 G Ex ia IIC T6
protection II 1 D Ex ta IIIC T80°C
Style “XC” = moulded coil; no safety barrier required.
protection II 2 G Ex eb IIC T4
protection II 2 D Ex tb IIIC T130°C